Image quality assessment test charts and objective image quality measurement systems may be used to evaluate the printer sub-system health before artifacts become objectionable to human observers. Diagnostic images may be printed to allow measurement of a number of system performance attributes, such as: density, banding, streak, granularity, mottle, color, gloss, gloss uniformity, edge gradient, raggedness, sharpness, background, registration, line width, and satellite measurements. By comparing these measurements to historical values or ideal values of the same measurements, preventive maintenance suggestions may be generated to avoid both unnecessary maintenance and objectionable print quality.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for controlling print quality of an image printed by a printing device comprising: a) printing a diagnostic image; b) measuring a plurality of image quality attributes of the diagnostic image; c) comparing image quality attributes, including density, banding, streak, granularity, mottle, color, gloss, gloss uniformity, edge gradient, raggedness, sharpness, background, registration, line width, and satellite measurements, to a predetermined value and historical usage values for respective same image quality attributes of the printing device to determine a preventive maintenance suggestion; and d) adjusting the printing device according to the preventive maintenance suggestion, thereby controlling print quality of the image before the quality becomes objectionable to an end user.
2. The method according to claim 1 , wherein step d) comprises at least one of automatically adjusting the printing device and instructing a user to make a specific adjustment to the printing device.
3. The method according to claim 2 , wherein step b) comprises measuring banding.
4. The method according to claim 3 , wherein the preventive maintenance suggestion comprises at least one of instructing the user to replace a development station gudgeon of the printing device, instructing the user to replace a development shell drive sprocket of the printing device, and instructing the user to clean a drive chain of the printing device.
5. The method according to claim 2 , wherein the preventive maintenance suggestion comprises instructing the user to replace a fuser roller of the printing device when the measurement of gloss changes, prior to a point in time when said image becomes objectionable to an end user.
6. The method according to claim 2 , wherein step b) comprises measuring background, satellite, and line width.
7. The method according to claim 6 , wherein the preventive maintenance suggestion comprises adjusting an environmental control unit of the printing device.
8. The method according to claim 2 , wherein step b) comprises measuring satellite and background for a particular color.
9. The method according to claim 8 , wherein the preventive maintenance suggestion comprises adjusting a concentration of toner of the particular color.
10. The method according to claim 2 , wherein step b) comprises measuring density to determine minimum density (D min ) and maximum density (D max ).
11. The method according to claim 10 , wherein the preventive maintenance suggestion comprises performing a linearization run.
12. The method according to claim 2 , wherein step b) comprises measuring color-to-color registration.
13. The method according to claim 12 , wherein the preventive maintenance suggestion comprises performing a registration calibration run.
14. The method according to claim 2 , wherein step b) comprises measuring streaking.
15. The method according to claim 14 , wherein the preventive maintenance suggestion comprises at least one of maintaining a fuser oiler of the printing device, cleaning a primary charger of the printing device, and checking the roller for excessive oil.
16. The method according to claim 2 , wherein step b) comprises measuring a hue shift.
17. The method according to claim 16 , wherein the preventive maintenance suggestion comprises one of using an alternate linearization table and using a different screen set.
18. The method according to claim 1 , wherein step b) is carried out using at least one of a flatbed scanner, a gloss meter and an optical image analyzer.
19. The method according to claim 1 , wherein step c) is carried out using a controller.
20. A method for tracking image quality attributes of a printed image from a printing device and predicting a preventive maintenance schedule, comprising: a) printing a diagnostic image; b) scanning the diagnostic image to measure a plurality of measured image quality attributes including density, banding, streak, granularity, mottle, color, gloss, gloss uniformity, edge gradient, raggedness, sharpness, background, registration, line width, and satellite measurements; c) comparing the measured image quality attributes to a corresponding predetermined image quality attribute ideal and to historical usage values of respective same image quality attributes of the printing device stored in a memory of a controller; and d) adjusting the printing device to bring the measured image quality attributes closer to the corresponding predetermined image quality attribute ideal, at a preventive maintenance schedule, thereby controlling print quality of the image before the quality becomes objectionable to an end user.
21. The method according to claim 20 , wherein the plurality of measured image quality attributes includes each of density, banding, streak, granularity, mottle, color, gloss, gloss uniformity, edge gradient, raggedness, sharpness, background, registration, line width, and satellite measurements.
22. The method according to claim 20 , wherein the corresponding predetermined image quality attributes are entered by a user into a memory of the controller.
23. A method for controlling the print quality of an image printed by a printing device comprising: a) printing a diagnostic image; b) scanning the diagnostic image with a flatbed scanner to measure density, banding, streak, granularity, mottle and color; c) scanning the diagnostic image with a gloss meter to measure gloss and gloss uniformity; d) scanning the diagnostic image with an optical image analyzer to measure edge gradient, raggedness, sharpness, background, line width, registration and satellite measurements; e) comparing a plurality of the density, banding, streak, granularity, mottle, color, gloss, gloss uniformity, edge gradient, raggedness, sharpness, background, line width, registration, and satellite measurements to a predetermined value and to a historical usage value for a respective same image quality attribute of the printing device to determine a preventive maintenance suggestion; and f) adjusting the printing device according to the preventive maintenance suggestion.
24. The method according to claim 23 , wherein step b) is carried out offline relative to step a).
25. A printing device comprising: a printer receiving an input media and outputting an output media having an image applied thereupon; a flatbed scanner capable of measuring density, banding, streak, granularity, mottle and color; a gloss meter is capable of measuring gloss and gloss uniformity; an optical image analyzer capable of measuring edge gradient, raggedness, sharpness, background, line width, registration, and satellite measurements; and a controller receiving data from the flatbed scanner, the gloss meter and the optical image analyzer; wherein said printer periodically produces the image as a diagnostic image having a test chart applied thereupon; and wherein the test chart is passed through the flatbed scanner, the gloss meter and the optical image analyzer to obtain a plurality of image quality attributes, and wherein said controller receives the plurality of image quality attributes and compares the plurality of image quality attributes to a predetermined value and a historical usage value for a respective same image quality attribute of the printing device to determine a preventive maintenance suggestion, and, adjusts the printing device according to the preventive maintenance suggestion, thereby controlling print quality of the image from becoming objectionable to an end user.
26. The printing device according to claim 25 , wherein the plurality of image quality attributes include at least two of density, banding, streak, granularity, mottle, color, gloss, gloss uniformity, edge gradient, raggedness, sharpness, background, registration, line width, and satellite measurements.
27. A computer readable media for controlling the print quality of an image printed by a printing device comprising: a code segment for obtaining a plurality of image quality attributes of a printed diagnostic image, wherein the plurality of image quality attributes include density, banding, streak, granularity, mottle, color, gloss, gloss uniformity, edge gradient, raggedness, sharpness, background, registration, line width, and satellite measurements; a code segment for comparing the plurality of the image quality attributes to one of a predetermined value and a historical usage value for a respective same image quality attribute of the printing device; a code segment for determining a preventive maintenance suggestion; and a code segment for adjusting the printing device according to the preventive maintenance suggestion when the preventive maintenance suggestion may be carried out automatically.
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January 18, 2005
August 17, 2010
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